Dendrimer compositions and their use in treatment of diseases of the eye

ABSTRACT

The present invention provides compositions comprising PAMAM dendrimers conjugated with one or more biologically active agents, and their use systemically to target activated microglia/macrophages in retina/choroid and generally, inflammatory and/or angiogenic diseases of the eye.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/986,495, filed on Apr. 30, 2014, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

Microglia are the resident macrophages of the brain and retina. They become activated in diseases such as diabetes and retinal degeneration where cells die, causing microglia to phagocytose cellular debris. Activation of retinal microglia occurs in a mouse model of ischemia/reperfusion injury (I/R), as occurs in inflammatory diseases of the eye, including glaucoma, age related macular degeneration (AMD), diabetic retinopathy and branch vein occlusion. Retinal vascular occlusion, be it by high intra-ocular pressure in the I/R model or thrombus in BVO, causes a decrease in blood flow within the eye resulting in retinal ischemia. This causes death of neurons initiating further activation of microglia.

Exudative (wet form) AMD is characterized by serous or hemorrhagic separation of the retinal pigment epithelium or neurosensory layer. Patients may develop choroidal neovascularization (CNV), which is manifested as fluid accumulation, hemorrhage, and/or lipid exudation.

The earliest stage of diabetic retinopathy (DR) is characterized by retinal vascular abnormalities including microaneurysms (saccular out-pouchings from the capillary wall), intraretinal hemorrhages, and cotton-wool spots (nerve fiber layer infarctions). As the disease progresses, the gradual closure of retinal vessels results in retinal ischemia, giving rise to signs including venous abnormalities (beading, loops), intraretinal microvascular abnormalities, and increasing retinal hemorrhage and exudation. Non-proliferative diabetic retinopathy is graded as mild, moderate, severe, and very severe according to the presence and extent of the above lesions.

The more advanced stage of DR involves the formation of new blood vessels, induced by the retinal ischemia, which spreads out either from the disc (neovascularization of the disc, NVD) or from elsewhere in the retina (neovascularization elsewhere, NVE). New vessels extending into the vitreous can cause vitreous hemorrhage, and tractional retinal detachments associated with accompanying contractile fibrous tissue (New FIG. 1 ).

Dendrimers are a group of nanostructured polymers that have the potential to deliver drugs and small molecule therapies because of their large number of functional groups, to intracellular domains. Kannan et al has shown the therapeutic utility of a dendrimer-based therapies in treating a rabbit model cerebral palsy (CP). This rabbit model replicates the neuro-inflammation seen in the adult brain during CP.

To date, the only treatment conclusively demonstrated to be of long term benefit for DR is focal laser photocoagulation.

The standard treatment for patients with AMD is intravitreal injections of anti-VEGF into the eye, and there have been studies that have shown that anti-VEGF therapy may be useful in diabetic macular edema (DME). However, systemic delivery would have many advantages beyond current treatments as there are at present no systemic treatments available for ischemic retinopathies or AMD. These advantages include less frequent injections due to retention in microglia and ability to delivery systemically, avoiding frequent intraocular injections as in current anti-VEGF therapies, or of drugs or drug releasing implants from erodable or non-erodable sustained release devices.

Currently, there are no targeted therapies for AMD or DR. Targeting the activated microglia/macrophages from systemic administration can increase efficacy of the drugs and reduce side effects.

SUMMARY OF THE INVENTION

In accordance with an embodiment, the present inventors investigated the ability of systemically delivered dendrimers to target activated microglia in retina in ischemic retina. Microglial activation was induced an ischemia/reperfusion injury. The differential uptake of dendrimers between normal and ischemic retina was compared.

The inventors surprisingly found that the PAMAM dendrimers were able to target one key cell type in retinal neuroinflammation, activated microglia/macrophages (mi/ma). Retention by activated microglia/macrophages (mi/ma) occurred whether the dendrimer was delivered intravenously or intravitreally. Furthermore, the microglia and the retinal pigment epithelial cells retained dendrimer while other cell types in the eye and other organs did not take up the dendrimer. The dendrimers remained in mi/ma for an extended period of time, 21 days, the longest time point evaluated in this study.

In accordance with the embodiment, the present inventors, also administered dendrimers, systemically (intravenous), into animals where retinal (RNV) and choroidal neovascularization (CNV) was induced by a sub-retinal lipid injection. The differential uptake of dendrimers between normal and lipid-injected retina and choroids was compared.

The inventors found that the systemically administered dendrimers were selectively localized in the activated microglia/macrophages in the areas of RNV and the macrophages in the areas of CNV, but were not present in the fellow, uninjured eye.

In accordance with an embodiment, the present invention provides a method for treating an inflammatory and/or angiogenic disease in the eye of a subject comprising administering to the subject systemically, a composition comprising dendrimer nanoparticles, wherein the dendrimer nanoparticles comprise poly(amidoamine) (PAMAM) hydroxyl-terminated dendrimers covalently linked to at least one biologically active agent, in an amount effective to suppress or inhibit the inflammatory and/or angiogenic disease in the eye.

The present invention provides a method to treat retinal and choroidal neovascularization, upon systemic administration of a dendrimer carrying an active biological agent.

In accordance with another embodiment, the present invention provides a method for treating an inflammatory and/or angiogenic disease in the eye of a subject comprising periodically administering to the subject intravenously, a composition comprising dendrimer nanoparticles, wherein the dendrimer nanoparticles comprise poly(amidoamine) (PAMAM) hydroxyl-terminated dendrimers covalently linked to a biologically active agent, in an amount effective to suppress or inhibit the inflammatory and/or angiogenic disease in the eye.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic showing the pathogenesis of AMD and how N-acetyl-cysteine (NAC) is a multimodal drug that can attenuate multiple pathways.

FIGS. 2A-2L show sections from control, non I/R, eyes 24 hours after intravitreal injection. 2A-D: Twenty four hours after injection of D-Cy5, there is no dendrimer retained in retina. 2E-H: Free Cy5 was present throughout inner retina and in the inner plexiform layer (IPL). Arrowheads indicate the internal limiting membrane (ILM). 2I-L: Injection of PBS resulted in no fluorescence in the Cy5 wavelength. [DAPI nuclear marker (blue). Dendrimer-Cy5 and Cy5 (red). Iba-1 microglia cell marker (green). bars=40 μm]

FIGS. 3A-3L show sections from ischemia/reperfusion eyes 24 hours after intravitreal injection. 3A-D. Dendrimer-Cy5 (red) is present in Iba-1+ microglia/macrophage (arrows). Arrow with asterisk indicates retinal Iba1+ cell with dendrimer shown in inset. 3E-H. Higher magnification of D-Cy5 (red) in Iba-1+ microglia. Arrow with asterisk indicates subretinal Iba1+ cell with dendrimer shown in inset. 3I-L. Cy5 or free dye is throughout inner retina and not associated with Iba-1+ microglia (arrow heads). [DAPI (blue), Iba-1 (green), D-Cy5 and Cy5 (red); NFL=nerve fiber layer, INL=inner nuclear layer, ONL=outer nuclear layer; 3A-D and 3I-L bar=40 μm, 3E-H bar=20 μm.]

FIGS. 4A-4L show 72 hrs after intravitreal injection. 4A-D. D-Cy5 is still present in microglia (arrows) and RPE cells (left side, linear fluorescence) in I/R eyes. Arrow with asterisk indicates Iba1+ cell in inner retina with dendrimer shown in inset. 4E-H. Higher magnification of D-Cy5 in microglia/macrophage (arrows). Arrow with asterisk indicates subretinal Iba1+ cell with dendrimer shown in inset. 4I-L. D-Cy5 was not present in non-I/R control eyes. [DAPI (blue), D-Cy5 (red), NFL=nerve fiber layer, INL=inner nuclear layer, ONL=outer nuclear layer; 4A-D and 3I-L bars=40 μm, 4E-H bars=20 μm].

FIGS. 5A-5L show twenty one days after intravitreal injection. 5A-D. D-Cy5 remains in Iba-1+ cells in I/R eyes (arrows). Some appear to be subretinal macrophages (left arrows). Arrow with asterisk indicates subretinal Iba1+ cell with dendrimer shown in inset. 5E-H. Retina of D-Cy5 injected eyes after I/R at higher magnification. Arrow with asterisk indicates Iba1+ cell in inner retina with dendrimer shown in inset. 5I-L, D-Cy5 wavelength fluorescence is not present in non-I/R eyes receiving PBS (fluorescence control). [DAPI (blue), D-Cy5 and Cy5 (red), Iba-1 (green); 5A-D and 5I-L bars=40 μm, 5E-H bars=20 μm].

FIGS. 6A-6P show sections of retinas from I/R eyes 24 hr after intravenous injection. 6A-H. D-Cy5 colocalizes with Iba-1 in labeled cells (green) in retina and also appears to be in RPE cells (bottom left). Arrow with asterisk indicates subretinal Iba1+ cell with dendrimer shown in inset. 6E-H. Higher magnification of the same area as in 6A-D. 5I-L. Free Cy5 dye is still present in choroid after 24 hrs. 6M-P. There is no fluorescence in the Cy5 wavelength in eyes receiving PBS intravenously. [DAPI (blue), D-Cy5 and Cy5 (red), Iba-1 (green); 6A-D and 6I-L bars=40 μm, 6E-H bars=20 μm].

FIGS. 7A-7L show sections of retinas 72 hours post intravenous D-Cy5 administration. 7A-D. There are many Iba-1+ cells in I/R retinas and a few in this field have D-Cy5 colocalized. 7E-H. Colocalization (yellow) is shown at higher magnification. 7I-L, No cells have D-Cy5 in non-I/R control eyes. [DAPI (blue). D-Cy5 and Cy5 (red). Iba-1 (green); 7A-D and 7I-L bars=40 μm, 7E-H bars=20 μm].

FIGS. 8A-8L show sections of retina and choroid 21 days after D-Cy5 injection. 8A-D. I/R retina still has Cy-5 colocalized with an Iba-1+ cell (arrow). 8E-H. D-Cy5 colocalization with Iba-1 shown at higher magnification in a ramified Iba-1+ cell. 8I-L. D-Cy5 administration to non-I/R control eyes. 8A-H arrows mark colocalization of D-Cy5 (red) and Iba-1 labeled cells (green). [DAPI (blue), D-Cy5 and Cy5 (red); 8A-D and 8I-L bars=40 μm, 8E-H bars=15 μm]

FIGS. 9A-9D show quantification of Iba-1+ cells in retina. Imaris software was trained to count Iba-1⁺ cells in sections for retina from ora serrate to ora serrata. 9A. There was a significant increase in the number of Iba-1⁺ cells in I/R retinas (p<0.01). 9B. The software was trained only to select soma cells not processes that had both Iba-1 label only (yellow arrows) or Iba-1 as well as D-Cy5 (white arrows) in this 3-D surface volume. The total number of microglia/macrophages (green) and those with D-Cy5 are shown at all three time points after intravitreal (9C) and intravenous (9D) administration to I/R eyes. These values are significantly greater than in non-I/R retinas where no cells in retina had D-Cy5.

FIGS. 10A-10C show quantification of D-Cy5 levels in posterior eye cups by fluorescence spectroscopy, after extraction of D-Cy5 from tissue. 10A) dendrimer levels upon single intravitreal injection of 20 μg of D-Cy5, shows significant difference between non I/R and I/R eyes. 10B) D-Cy5 levels upon single intravenous injection of 600 μg; 10C) Comparison of dendrimer levels in I/R eyes in both intravitreal and intravenous (at 30× higher dose) routes are comparable (n=8, student t-test). For quantification, posterior eye cups were homogenized lyophilized, and dendrimers were extracted into a small volume of methanol. Fluorescence was measured using previously established protocols, with appropriate D-Cy5 calibration and controls. D-Cy5 was near detection limit (NDL) in healthy eyes (3 and 21 days). (* indicates p<0.01 when I/R is compared to non-I/R)

FIG. 11 shows the synthesis of D-TA and Cy5-D-TA conjugates.

FIGS. 12A-12C (new) show chromatograms depicting the purity of the 12A) D-TA and 12B) Cy5-D-TA conjugates. 12C) shows the size, zeta potential, and molecular weights of the conjugates.

FIGS. 13A-13B (new) depict the NMR characterization of the 13A) D-TA and 13B) Cy5-D-TA conjugates.

FIG. 14 shows the in-vitro release of TA from D-TA in a simulated vitreous humor model.

FIG. 15 depicts the biodistribution of D-Cy5 in various organs and clearance with time. The organ uptake was quantified, using D-Cy5 fluorescence measurements, against appropriate calibration curves (n=8). (* indicates p<0.01 when 24 is compared to 72 hr; # indicates p<0.05).

FIGS. 16A-16B show gel permeation chromatographs of the synthesized bifunctional dendrimer. 16A shows an elution time of 14.84 min from the column which differed from the elution time of G4-OH dendrimer (elution time 14.42 min). This indicates formation of a new compound and that there is only a minor shift in elution time indicating that the structural property of G4-OH dendrimer has not changed significantly. Appearance of a new peak simultaneously in 16.69 min at 647 nm (UV λmax for Cy5) and 645 nm (fluorescence emission of Cy5), which is different from the Cy5 peaks (20.39 min) 16B, confirms successful conjugation of dye to the dendrimers.

FIGS. 17A-17L depict sections from non-ischemia/reperfusion eyes 24 hours after intravenous injection. 17A-D. Dendrimer-Cy5 (red) is present in Iba-1+ microglia in choroid (arrows). Inset: Higher magnification of D-Cy5 (red) in Iba-1+ microglia. 17E-H. Free Cy5 is throughout choroid (asterisk) and not associated with Iba-1+ microglia (arrow). 17I-L. There is no Cy5 wavelength fluorescence in the eye when PBS is administered intravenously (negative control). [DAPI (blue), Iba-1 (green), D-Cy5 and Cy5 (red); NFL=nerve fiber layer, INL=inner nuclear layer, ONL=outer nuclear layer; 17A-D and 17I-L bar=40 μm, 17E-H bar=20 μm.]

FIGS. 18A-18I show the qualitative assessment of D-Cy5 levels in the kidney as a function of time, using confocal microscopy. 18A-C. (top panel) cross sections of kidneys at 24 hrs, 72 hrs and 21 days respectively post D-Cy5 injection intravenously. D-Cy5 (red) upon intravenous injection were rapidly cleared from systemic circulation and found predominately accumulated in the proximal tubules of the kidney cortex and were excreted at later time points (72 hrs & 21 days). Below are the HPLC chromatograms of the kidney extract proving the fluorescence signals from kidney cortex are from intact D-Cy5 (based on the retention time 14.92 min), whereas the time increases the peak signal decreases indicating D-Cy5 excretion via urine and is in good agreement with the confocal images.

FIGS. 19A-19B are graphs depicting the semi-quantification of dendrimers in posterior eye cup. D-Cy5 was administered either intravenously (19A) or intravitreally (19B), and quantified both in the injured (I/R) and healthy (non-I/R) eye at 24 hours, 72 hours, 21 days. Significant differences in the uptake between injured and non-injured eye is seen.

FIG. 20 is an illustration of the rat model of CNV and treatment protocols.

FIG. 21 shows a choroidal flat mount where CNV has developed due to lipid injection causing development of abnormal blood vessels (neovascularization) (Isolectin, Blue panel). Accumulation of Microglia/Macrophages (Iba-1, Green panel) and dendrimers localized in microglia/macrophages in the CNV area (D-Cy5, Red panel). All the channels are overlaid to show the co-localization (Merged)

FIG. 22 is a graph depicting the mean CNV areas in non-treated and D-NAC treated choroids in lipid injected rat model. There is a significant reduction ˜80% in CNV area in D-NAC treated animals than compared to non-treated animals group. The data was statically analyzed using tailed student t test with Welch correction resulting significant results with p=0.0003 for a sample size n=6.

FIG. 23 shows retinal inflammation and neovascularization caused by subretinal injection of lipid. Retinal neovascularization (RNV) formed in the retina showing tortuous abnormal blood vessels stained by Isolectin (Blue panel) shown in white circle. Migration and accumulation of inflammatory microglia cells stained by Iba-1 (Green panel) and co-localization of D-Cy5 in microglial cells (D-Cy5, Red panel). The merged panel shows the combined effect of inflammation and neovascularization and colocalization of dendrimers specifically in inflammatory cells indicated by white arrows (Merged).

FIG. 24 shows the RNV area in retinal flatmount indicating that dendrimers (Red) are accumulated in inflammation area and uptaken by microglial cells. We have also observed migration of retinal microglia towards the injured (inflammation) area as indicated by white arrows. (Blue-Isolectin) blood vessels, (Green, Iba-1) Microglia/macrophages and (red or pink) D-cy5.

FIGS. 25A-25B depict the effect of systemic free NAC, D-NAC (20 mg/kg on NAC basis), or PBS, on CNV, assessed in a blinded manner, using established choroidal flat mount protocols. D-NAC treated animals showed significant decrease in CNV areas when compared to PBS. Free NAC showed some decrease that was not significant. CNV areas were assessed using morphometric analysis (yellow delineation) in Image-J software. Panel A shows the PBS choroid with larger CNV and increased population of macrophages (green) in the bleb area, whereas panel B shows the efficacy of D-NAC with reduced CNV and macrophage accumulation. The vasculature was stained with GSA lectin (blue), and macrophages are stained with IBA-1 (Green). Values were analyzed using Mann-Whitney t-test with n=12 and P<0.001.

FIG. 26 shows flat mount image analysis of (20× magnification) of choroids for macrophage accumulation in the bleb area surrounding the CNV. Macrophages were stained with IBA-1 (Green) and D-Cy5 is red. Macrophage cell count analysis showed a ˜63% reduction in number of macrophages cells, and a ˜60% reduction in activated macrophages upon D-NAC compared to PBS treatment, with near 90%+ colocalization of activated macrophages and dendrimers. The cell count analysis were done using Imaris (Bitplane) software using surface function with smoothing factor and cell size threshold of 8-12 μm diameter with split function. Activated and resting macrophages were counted based on cell shape (amoeboid versus ramified) using cell surface to volume ratio with sphericity of 0.758 add ellipiticity function 0.298 as threshold. Colocalization of D-Cy5 was assessed using spot function. N=6 eyes for each group, 3 areas/choroid were analyzed, and averaged.

FIGS. 27A-27C depict that the choroids from the different groups were analyzed using ELISA (n=8 choroids/group). While free NAC was not effective compared to controls, D-NAC showed significant attenuation of pro-inflammatory cytokines (27A and B). *** denotes p<0.001. D-NAC also enhanced anti-inflammatory IL-10 (27C) * denotes p<0.01.

FIGS. 28A-28C depict flat mount retinas (40× magnification) with GSA-stained blood vessels, IBA-1 for mi/ma, and dendrimer (D-Cy5); 28A) ‘Healthy’, non pathologic area of same retina with regular blood vessel structure and resting mi/ma (ramified) (white arrows), and no D-Cy5; 28B) Pathological area of the same retina near the bleb showing abnormal vessels, activated mi/ma (‘round’ and amoeboid) and ‘spiked’ dendrimers co-localized in activated mi/ma (white arrows); 28C) D-NAC treated retina showing both populations (i) resting microglia (ramified) (yellow arrows) and (ii) activated mi/ma (amoeboid) with dendrimer (white arrows) suggesting the therapeutic effect of D-NAC in quieting microglial activation.

FIGS. 29A-29B. 29A) is a bar graph showing retinal microglial counts in the retina for PBS and D-NAC treatment. The D-NAC treatment reverses the activated microglia phenotype. 29B) depicts 3-D representative images of the PBS and D-NAC treated microglia.

FIGS. 30A-30C show the results from the retinas from the different groups analyzed by ELISA (n=8/group). While free NAC was not effective compared to PBS, D-NAC showed significant attenuation of pro-inflammatory cytokines. D-NAC also enhanced anti-inflammatory (IL-10). *** denotes p<0.001.

FIGS. 31A-31B show the effect of TA on CNV suppression. 31A shows a choroidal flat mount where CNV has developed due to lipid injection (HpODE) causing development of abnormal blood vessels (31A, C, E, G) and then treated with D-TA (31B, D, F, H). 31B is a bar graph representing the measurement of CNV areas (mm²) of HpODE, D-TA, or free TA (F-TA). About 95% of the reduction of CNV can be attributed to a dual anti-inflammatory and anti-angiogenic effect.

FIG. 32 shows preliminary CNV area analysis of D-NAC+D-TA treated choroids: On Day 21, PBS-treated choroids show significantly larger CNV area with fully formed irregular blood vessels compared to D-NAC choroids treated on Day 11, suggesting effectiveness for late AMD. On Day 21, the D-NAC treated (on Day 11) chorids show a lower CNV area compared to PBS choroids on Day 10, suggesting regression.

FIGS. 33A-33C depict representative images (right) showing CNV of PBS-Day 21 (33A), and PBS-Day 10 (33B), and D-NAC+D-TA-Day 21 (33C). ** indicates p<0.01. Scale bar at 100 μm.

FIGS. 34A-34C show that dendrimers target retinal microglia/macrophage upon both systemic and intravitreal routes, comparable at 30× higher systemic doses.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with one or more embodiments, the present invention discloses the ability of PAMAM dendrimers to target one key cell type in retinal neuroinflammation, activated microglia via intravenous, systemic injection. Surprisingly, retention by activated microglia occurred whether the dendrimer was delivered intravenously when compared to intravitreal injection. Furthermore, the microglia retained dendrimer while other cell types did not take up the dendrimer. The dendrimers remained in microglia for an extended period of time, 21 days, the longest time point evaluated in this study. Activated microglia/macrophages have been associated with inflammatory and/or angiogenic retinal diseases such as macular degeneration, diabetic retinopathy, glaucoma, and retinopathy of prematurity. Ischemia-reperfusion (I/R) injury has been used to model certain aspects of chronic glaucoma, diabetic retinopathy and branch vein occlusion (BVO). I/R injury causes occlusion of both retinal and choroidal blood vessels, resulting in reduced blood flow and tissue hypoxia. The above conditions were reported to cause disruption of blood retinal barriers (BRB), activation of resident microglia/macrophages, infiltration of microglia and macrophages from choroid and systemic circulation, elevated production of cytokines (TNF-α, Inf-α, TGF-β, IL-1β and IL-6) and death of retinal ganglion cells (RGCs).

An important aspect of the inventive methods was the fact that the D-Cy5 was retained almost exclusively in activated microglia, whether they were delivered intravenously or intravitreally. Intravenous administration is safer than intravitreal, but intravitreal is currently the standard of care for anti-VEGF therapies used in treating exudative age-related macular degeneration (wet AMD) and diabetic macular edema. D-Cy5 retention in microglia at 21 days post femoral injection is also very significant in that repeated injections like current anti-VEGF therapies would not require intravitreal injection.

This method was further supported by the surprising finding that in a rat choroid neovascularization (CNV) model, systemic intravenous injection of a dendrimer compound of the present invention conjugated to N-acetal-cysteine significantly reduced the area of CNV in the treated animals compared to controls.

In accordance with some embodiments, the present invention provides a composition comprising dendrimer nanoparticles, wherein the dendrimer nanoparticles comprising predominantly hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers covalently linked to at least one or more biologically active agents, which can be the same or different, in an amount effective to suppress or inhibit an inflammatory disease in the eye. As used herein, the term “predominantly hydroxyl-terminated” means that a majority of the surface functional groups of the dendrimers are OH groups. In some embodiments, the dendrimers can have a mixture of different functional groups.

Thus, in accordance with another embodiment, the present invention provides a method for treating an inflammatory and/or angiogenic disease in the eye of a subject by administering a composition comprising dendrimer nanoparticles intravenously; wherein the dendrimer nanoparticles comprise one or more ethylene diamine-core poly(amidoamine) (PAMAM) hydroxyl-terminated dendrimers covalently linked to at least one or more biologically active agents, which can be the same or different, in an amount effective to suppress or inhibit the inflammatory and/or angiogenic disease in the eye.

As used herein, the term “PAMAM dendrimer” means poly(amidoamine) dendrimer, which may contain different cores, with amidoamine building blocks. The method for making them is known to those of skill in the art and generally, involves a two-step iterative reaction sequence that produces concentric shells (generations) of dendritic β-alanine units around a central initiator core. This PAMAM core-shell architecture grows linearly in diameter as a function of added shells (generations). Meanwhile, the surface groups amplify exponentially at each generation according to dendritic-branching mathematics. They are available in generations G0-10 with 5 different core types and 10 functional surface groups. The dendrimer-branched polymer may consist of polyamidoamine (PAMAM), polyester, polyether, polylysine, or polyethylene glycol (PEG), polypeptide dendrimers. It will be understood by those of skill in the art that the dendrimer compositions described and claimed herein can be dendrimers of G3 to G10 in range, typically, G4 or G5 in range, with mixtures of different G levels also possible.

In accordance with some embodiments, the PAMAM dendrimers used can be generation 4 dendrimers, with hydroxyl groups attached to their functional surface groups.

In some embodiments, the dendrimers are in nanoparticle form and are described in detail in international patent publication No. WO2009/046446, which is incorporated by reference herein.

As used herein, the term “inflammatory disease of the eye” means diseases of the eye associated with inflammation of the tissues of the eye, including, for example, age-related macular degeneration (ARMD), retinitis pigmentosa, optic neuritis, infection, sarcoid, sickle cell disease, retinal detachment, temporal arteritis, retinal ischemia, arteriosclerotic retinopathy, hypertensive retinopathy, retinal artery blockage, retinal vein blockage, hypotension, diabetic retinopathy, macular edema, and also includes angiogenic diseases including, for example, choroidal neovascularization.

In accordance with an embodiment, the present invention provides for the use of the compositions disclosed herein, for treating an inflammatory and/or angiogenic disease in the eye of a subject comprising administering to the subject systemically, in an effective amount, to suppress or inhibit the inflammatory disease in the eye of the subject.

In accordance with another embodiment, the present invention provides a method for attenuating or treating disorders of the eye in a subject caused by oxidative and ER stress in a cornea of the subject comprising administering to the subject an effective amount of a dendrimer composition comprising a biologically active agent.

An active agent and a biologically active agent are used interchangeably herein to refer to a chemical or biological compound that induces a desired pharmacological and/or physiological effect, wherein the effect may be prophylactic or therapeutic. The terms also encompass pharmaceutically acceptable, pharmacologically active derivatives of those active agents specifically mentioned herein, including, but not limited to, salts, esters, amides, prodrugs, active metabolites, analogs and the like. When the terms “active agent,” “pharmacologically active agent” and “drug” are used, then, it is to be understood that the invention includes the active agent per se as well as pharmaceutically acceptable, pharmacologically active salts, esters, amides, prodrugs, metabolites, analogs etc. The active agent can be a biological entity, such as a virus or cell, whether naturally occurring or manipulated, such as transformed.

In some embodiments, the biologically active agents can include detectable moieties. As used herein, the term “detectable moiety” means that this specific portion of the molecule comprises at least one or more imaging agents which are attached to the dendrimer molecule. At least one of the imaging agents is a fluorescent dye. The dyes may be emitters in the visible or near-infrared (NIR) spectrum. Known dyes useful in the present invention include carbocyanine, indocarbocyanine, oxacarbocyanine, thiiicarbocyanine and merocyanine, polymethine, coumarine, rhodamine, xanthene, fluorescein, borondipyrromethane (BODIPY), Cy3, Cy5, Cy5.5, Cy7, VivoTag-680, VivoTag-S680, VivoTag-S750, AlexaFluor660, AlexaFluor680, AlexaFluor700, AlexaFluor750, AlexaFluor790, Dy677, Dy676, Dy682, Dy752, Dy780, DyLight547, Dylight647, HiLyte Fluor 647, HiLyte Fluor 680, HiLyte Fluor 750, IRDye 800CW, IRDye 800RS, IRDye 700DX, ADS780WS, ADS830WS, and ADS832WS.

Organic dyes which are active in the NIR region are known in biomedical applications. However, there are only a few NIR dyes that are readily available due to the limitations of conventional dyes, such as poor hydrophilicity and photostability, low quantum yield, insufficient stability and low detection sensitivity in biological system, etc. Significant progress has been made on the recent development of NIR dyes (including cyanine dyes, squaraine, phthalocyanines, porphyrin derivatives and BODIPY (borondipyrromethane) analogues) with much improved chemical and photostability, high fluorescence intensity and long fluorescent life. Examples of NIR dyes include cyanine dyes (also called as polymethine cyanine dyes) are small organic molecules with two aromatic nitrogen-containing heterocycles linked by a polymethine bridge and include Cy5, Cy5.5, Cy7 and their derivatives. Squaraines (often called Squarylium dyes) consist of an oxocyclobutenolate core with aromatic or heterocyclic components at both ends of the molecules, an example is KSQ-4-H. Phthalocyanines, are two-dimensional 18π-electron aromatic porphyrin derivatives, consisting of four bridged pyrrole subunits linked together through nitrogen atoms. BODIPY (borondipyrromethane) dyes have a general structure of 4,4′-difluoro-4-bora-3a,4a-diaza-s-indacene) and sharp fluorescence with high quantum yield and excellent thermal and photochemical stability.

In accordance an embodiment, the biologically active agent is selected from the group consisting of enzymes, receptor antagonists or agonists, hormones, growth factors, antibodies, oligonucleotides, siRNAs, microRNAs, vitamin A, vitamin C, vitamin E, beta-carotene, and small molecules.

In accordance with another embodiment, the small molecules are selected from the group consisting of anti-inflammatory agents such as steroids, including methyl prednisone, dexamethasone, non-steroidal anti-inflammatory agents, including COX-2 inhibitors, corticosteroid anti-inflammatory agents, gold compound anti-inflammatory agents, immunosuppressive anti-inflammatory and anti-angiogenic agents, salicylate anti-inflammatory agents, ranibizumab, minocycline, anti-VEGF agents, including aflibercept, and rapamycin. They can also include anti-oxidants such as N-acetyl cysteine, omega-3 fatty acid derivatives such as resolving and neuroprotectin-D1 (NPD1).

In accordance with some other embodiments, the molecules can include antibodies, including, for example, daclizumab, bevacizumab (Avastin®), ranibizumab) (Lucentis®), basiliximab, ranibizumab, and pegaptanib sodium or peptides like SN50, and antagonists of NFκβ.

In accordance with some embodiments, the biologically active agent can be N-acetyl cysteine (NAC) and/or triamcinolone acetonide (TA).

In some embodiments, the dendrimer compositions used in the methods described herein are generation-4, hydroxyl terminated PAMAM dendrimers (G4-OH) conjugated with one or more biologically active agents. For example, G4-OH dendrimers conjugated to NAC and/or TA can be used in the inventive methods.

In some embodiments, there is contemplated, theranostic compositions which would include at least one biologically active agent and at least one detectable moiety. For example, a theranostic composition could include a G4-OH or amine-G4-NH₂ dendrimer conjugated to NAC and to D-Cy5 to aid in visualization of the therapeutic or biologically active agent in the body.

Triamcinolone acetonide (4aS,4bR,5S,6aS,6bS,9aR,10aS,10bS)-4b-fluoro-6b-glycoloyl-5-hydroxy-4a,6a,8,8-tetramethyl-4a,4b,5,6,6a,6b,9a,10,10a,10b,11,12-dodecahydro-2H-naphtho[2′,1′:4,5]indeno[1,2-d][1,3]dioxol-2-one) is a synthetic corticosteroid used to treat various skin conditions, to relieve the discomfort of mouth sores, and in nasal spray form, to treat allergic rhinitis. It is a more potent derivative of triamcinolone, and is about eight times as potent as prednisone. As an intravitreal injection, triamcinolone acetonide has been used to treat various eye diseases and has been found useful in reducing macular edema. Drug trials have found it to be as efficient as anti-VEGF drugs in eyes with artificial lenses over a two-year period.

It will be understood that the dendrimer compositions used with the methods of the present invention can be in any suitable formulation. Examples of such formulations include one or more of a liposome, a microcapsule, and a nanocapsule.

Embodiments of the invention also include a process for preparing pharmaceutical products comprising the compounds. The term “pharmaceutical product” means a composition suitable for pharmaceutical use (pharmaceutical composition), as defined herein. Pharmaceutical compositions formulated for particular applications comprising the compounds of the present invention are also part of this invention, and are to be considered an embodiment thereof.

As used herein, the term “treat,” as well as words stemming there from, includes preventative as well as disorder remitative treatment. The terms “reduce,” “suppress,” “prevent,” and “inhibit,” as well as words stemming there from, have their commonly understood meaning of lessening or decreasing. These words do not necessarily imply 100% or complete treatment, reduction, suppression, or inhibition.

With respect to pharmaceutical compositions described herein, the pharmaceutically acceptable carrier can be any of those conventionally used, and is limited only by physico-chemical considerations, such as solubility and lack of reactivity with the active compound(s), and by the route of administration. The pharmaceutically acceptable carriers described herein, for example, vehicles, adjuvants, excipients, and diluents, are well-known to those skilled in the art and are readily available to the public. Examples of the pharmaceutically acceptable carriers include soluble carriers such as known buffers which can be physiologically acceptable (e.g., phosphate buffer) as well as solid compositions such as solid-state carriers or latex beads. It is preferred that the pharmaceutically acceptable carrier be one which is chemically inert to the active agent(s), and one which has little or no detrimental side effects or toxicity under the conditions of use.

The carriers or diluents used herein may be solid carriers or diluents for solid formulations, liquid carriers or diluents for liquid formulations, or mixtures thereof.

Solid carriers or diluents include, but are not limited to, gums, starches (e.g., corn starch, pregelatinized starch), sugars (e.g., lactose, mannitol, sucrose, dextrose), cellulosic materials (e.g., microcrystalline cellulose), acrylates (e.g., polymethylacrylate), calcium carbonate, magnesium oxide, talc, or mixtures thereof.

For liquid formulations, pharmaceutically acceptable carriers may be, for example, aqueous or non-aqueous solutions, suspensions, emulsions or oils. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, and injectable organic esters such as ethyl oleate. Aqueous carriers include, for example, water, alcoholic/aqueous solutions, cyclodextrins, emulsions or suspensions, including saline and buffered media.

Examples of oils are those of petroleum, animal, vegetable, or synthetic origin, for example, peanut oil, soybean oil, mineral oil, olive oil, sunflower oil, fish-liver oil, sesame oil, cottonseed oil, corn oil, olive, petrolatum, and mineral. Suitable fatty acids for use in parenteral formulations include, for example, oleic acid, stearic acid, and isostearic acid. Ethyl oleate and isopropyl myristate are examples of suitable fatty acid esters.

Parenteral vehicles (for subcutaneous, intravenous, intraarterial, or intramuscular injection) include, for example, sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's and fixed oils. Formulations suitable for parenteral administration include, for example, aqueous and non-aqueous, isotonic sterile injection solutions, which can contain anti-oxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions that can include suspending agents, solubilizers, thickening agents, stabilizers, and preservatives.

Intravenous vehicles include, for example, fluid and nutrient replenishers, electrolyte replenishers such as those based on Ringer's dextrose, and the like. Examples are sterile liquids such as water and oils, with or without the addition of a surfactant and other pharmaceutically acceptable adjuvants. In general, water, saline, aqueous dextrose and related sugar solutions, and glycols such as propylene glycols or polyethylene glycol are preferred liquid carriers, particularly for injectable solutions.

In addition, in an embodiment, the compounds of the present invention may further comprise, for example, binders (e.g., acacia, cornstarch, gelatin, carbomer, ethyl cellulose, guar gum, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, povidone), disintegrating agents (e.g., cornstarch, potato starch, alginic acid, silicon dioxide, croscarmelose sodium, crospovidone, guar gum, sodium starch glycolate), buffers (e.g., Tris-HCl, acetate, phosphate) of various pH and ionic strength, additives such as albumin or gelatin to prevent absorption to surfaces, detergents (e.g., Tween 20, Tween 80, Pluronic F68, bile acid salts), protease inhibitors, surfactants (e.g. sodium lauryl sulfate), permeation enhancers, solubilizing agents (e.g., cremophor, glycerol, polyethylene glycerol, benzlkonium chloride, benzyl benzoate, cyclodextrins, sorbitan esters, stearic acids), anti-oxidants (e.g., ascorbic acid, sodium metabisulfite, butylated hydroxyanisole), stabilizers (e.g., hydroxypropyl cellulose, hyroxypropylmethyl cellulose), viscosity increasing agents (e.g., carbomer, colloidal silicon dioxide, ethyl cellulose, guar gum), sweetners (e.g., aspartame, citric acid), preservatives (e.g., thimerosal, benzyl alcohol, parabens), lubricants (e.g., stearic acid, magnesium stearate, polyethylene glycol, sodium lauryl sulfate), flow-aids (e.g., colloidal silicon dioxide), plasticizers (e.g., diethyl phthalate, triethyl citrate), emulsifiers (e.g., carbomer, hydroxypropyl cellulose, sodium lauryl sulfate), polymer coatings (e.g., poloxamers or poloxamines), coating and film forming agents (e.g., ethyl cellulose, acrylates, polymethacrylates), and/or adjuvants.

The choice of carrier will be determined, in part, by the particular compound, as well as by the particular method used to administer the compound. Accordingly, there are a variety of suitable formulations of the pharmaceutical composition of the invention. The following formulations for parenteral, subcutaneous, intravenous, intramuscular, intraarterial, intrathecal and interperitoneal administration are exemplary, and are in no way limiting. More than one route can be used to administer the compounds, and in certain instances, a particular route can provide a more immediate and more effective response than another route.

Suitable soaps for use in parenteral formulations include, for example, fatty alkali metal, ammonium, and triethanolamine salts, and suitable detergents include, for example, (a) cationic detergents such as, for example, dimethyl dialkyl ammonium halides, and alkyl pyridinium halides, (b) anionic detergents such as, for example, alkyl, aryl, and olefin sulfonates, alkyl, olefin, ether, and monoglyceride sulfates, and sulfosuccinates, (c) nonionic detergents such as, for example, fatty amine oxides, fatty acid alkanolamides, and polyoxyethylenepolypropylene copolymers, (d) amphoteric detergents such as, for example, alkyl-β-aminopropionates, and 2-alkyl-imidazoline quaternary ammonium salts, and (e) mixtures thereof.

Injectable formulations are in accordance with the invention. The requirements for effective pharmaceutical carriers for injectable compositions are well-known to those of ordinary skill in the art (see, e.g., Pharmaceutics and Pharmacy Practice, J. B. Lippincott Company, Philadelphia, Pa., Banker and Chalmers, eds., pages 238-250 (1982), and ASHP Handbook on Injectable Drugs, Trissel, 15th ed., pages 622-630 (2009)).

In an embodiment, the term “administering” means that the compounds of the present invention are introduced into a subject, preferably a subject receiving treatment for a inflammatory related disease of the eye, and the compounds are allowed to come in contact with the one or more disease related cells or population of cells in vivo.

As used herein, the term “subject” refers to any mammal, including, but not limited to, mammals of the order Rodentia, such as mice and hamsters, and mammals of the order Logomorpha, such as rabbits. It is preferred that the mammals are from the order Carnivora, including Felines (cats) and Canines (dogs). It is more preferred that the mammals are from the order Artiodactyla, including Bovines (cows) and Swines (pigs) or of the order Perssodactyla, including Equines (horses). It is most preferred that the mammals are of the order Primates, Ceboids, or Simoids (monkeys) or of the order Anthropoids (humans and apes). An especially preferred mammal is the human.

It will be understood by those of ordinary skill that a dosing regimen used in the inventive methods can be any length of time sufficient to provide a reduction in the inflammatory disease and/or oxidative stress in the eyes of the subject. The term “chronic” as used herein, means that the length of time of the dosage regimen can be hours, days, weeks, months, or possibly years.

In a further embodiment, the compositions and methods of the present invention can be used in combination with one or more additional therapeutically active agents which are known to be capable of treating conditions or diseases discussed above. For example, the compositions of the present invention could be used in combination with one or more known therapeutically active agents, to treat inflammatory and/or angiogenic disease, or an oxidative stress related disease. Non-limiting examples of other therapeutically active agents that can be readily combined in a pharmaceutical composition with the compositions and methods of the present invention include drugs in the non-steroidal anti-inflammatory drug class (NSAID).

In accordance with an embodiment, the present invention provides a method for attenuating or treating disorder of the eye in a subject caused by inflammatory disease, oxidative stress, and/or angiogenesis in an eye of the subject comprising administering to the subject an effective amount of a composition comprising a dendrimer composition conjugated to a non-steroidal anti-inflammatory drug.

Examples of NSAIDS used in the methods of the present invention include mefenamic acid, aspirin, Diflunisal, Salsalate, Ibuprofen, Naproxen, Fenoprofen, Ketoprofen, Deacketoprofen, Flurbiprofen, Oxaprozin, Loxoprofen, Indomethacin, Sulindac, Etodolac, Ketorolac, Diclofenac, Nabumetone, Piroxicam, Meloxicam, Tenoxicam, Droxicam, Lornoxicam, Isoxicam, Meclofenamic acid, Flufenamic acid, Tolfenamic acid, elecoxib, Rofecoxib, Valdecoxib, Parecoxib, Lumiracoxib, Etoricoxib, Firocoxib, Sulphonanilides, Nimesulide, Niflumic acid, and Licofelone.

Typically, an attending physician will decide the dosage of the composition with which to treat each individual subject, taking into consideration a variety of factors, such as age, body weight, general health, diet, sex, compound to be administered, route of administration, and the severity of the condition being treated. By way of example, and not intending to limit the invention, the systemic dose of the compositions of the present invention can be about 0.0001 to about 1000 mg/kg body weight of the subject being treated, from about 0.01 to about 100 mg/kg body weight, from about 0.1 mg/kg to about 50 mg/kg, and from about 0.5 mg to about 25 mg/kg body weight In an embodiment of the present invention, patients are treated periodically with the dendrimer-drug compositions in accordance with a dosing regimen.

Thus, in accordance with another embodiment, the present invention provides a method for treating inflammatory and angiogenic diseases in the eye of a subject comprising periodically administering to the subject systemically, a composition comprising dendrimer nanoparticles, wherein the dendrimer nanoparticles poly(amidoamine) (PAMAM) hydroxyl-terminated dendrimers covalently linked to a biologically active agent, in an amount effective to suppress or inhibit the inflammatory disease in the eye.

It is contemplated that in an embodiment of the present invention, that the patients are treated with the anti-inflammatory dendrimer compositions, for example, a biweekly, monthly, bimonthly or trimonthly schedule.

EXAMPLES

High Performance Liquid Chromatography (HPLC) analysis. The purity of the dendrimer-Cy5 conjugates (D-Cy5) were analyzed using a Waters HPLC instrument (Waters Corporation, Milford, Mass.) equipped with Waters In-line degasser, binary pump, photodiode array (PDA) detector, multi fluorescence λ detector and auto sampler (maintained at 4° C.) interfaced with Empower software. The HPLC chromatogram was monitored simultaneously for absorbance at 210 nm for dendrimer and 650 nm for Cy5 using Waters 2998 PDA detector and fluorescence with excitation at 645 nm and emission at 662 nm using Waters 2475 fluorescence detector. The water/acetonitrile (0.1% w/w TFA) was freshly prepared, filtered, degassed, and used as a mobile phase. TSK-Gel ODS-80 Ts (250×4.6 mm, 25 cm length with 5 μm particle size) connected to TSK-Gel guard column was used. A gradient flow was used with initial condition being 90:10 (H₂O/ACN) and then gradually increasing the acetonitrile concentration to 10:90 (H₂O/ACN) in 30 min and returning to original initial condition 90:10 (H₂O/ACN) in 60 min with flow rate of 1 ml/min.

Dynamic light scattering and Zeta potential analysis. The particle size and ζ-potential of G4-OH and D-Cy5 conjugates were determined by dynamic light scattering (DLS) using a Zetasizer Nano ZS (Malvern Instrument Ltd. Worchester, U.K) equipped with a 50 mW He—Ne laser (633 nm). For sizing, the samples were dissolved in deionized water (18.2Ω) making a final concentration of 50 μg/mL. The solution was filtered through a cellulose acetate membrane (0.45 micron, PALL Life Science) and DLS measurements were performed at 25° C. with a scattering angle of 173°. Zeta potentials were calculated using the Smolokowsky model and measurements were performed in triplicate.

Animals & Ischemia reperfusion (I/R) injury. All procedures involving the animals conformed to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. BALB/c albino mice, each weighing ˜25 grams, housed in Wilmer animal facility at Johns Hopkins were used for transport as well as I/R studies. All surgeries were performed under ketamine (100 mg/Kg) and Xylazine (10 mg/kg) peritoneal anaesthesia. Six mice were used in each group at each time point. I/R injury was performed in the left eye by following the procedure described elsewhere. Briefly, the anterior chamber was cannulated with 30 gauze needle attached to a line infusing saline. The saline system is mounted on to a custom-made saline reservoir and elevated to certain height (calibrated to 90 mm Hg). The IOP was elevated to 90 mm Hg for 90 minutes and I/R injury and shut off of choroidal circulation was evidenced by blanching of the posterior segment via fundus examination through the operating microscope. After ischemia, the needle was immediately withdrawn for immediate blood reperfusion. The right eye had no I/R injury and served as control.

Dendrimer injection and Animal sacrifice. Six days post I/R injury, BALB/c mice were injected with dendrimer either intravitreally or intravenously. For intravitreal injections, 2 μL containing 20 μg of D-Cy5 was injected using a glass needle aided with a compression injector (Harvard apparatus, Holliston, Mass., USA) into the vitreous chamber. For intravenous injections, 600 μg of D-Cy5 dissolved in 100 μL of sterile PBS was injected via a 30 g needle into the femoral vein after making a small incision in the femoral region. Animals injected with free Cy5 and PBS served as positive or negative controls for this study. At appropriate time points (24 hrs, 72 hrs and 21 days) post dendrimer injections, the animals were anesthetized using ketamine/Xylazine and euthanized using a lethal dose of sodium pentobarbital. The eyes were immediately enucleated and processed for immunohistochemistry analysis.

Immunohistochemistry and confocal microscopy. Eyes were enucleated and fixed in 2% paraformaldehyde (PFA) in PBS. The anterior chamber of the eye was removed and eye cup cryopreserved using previously established protocols (Lutty et al, IOVS, 1993). The eyes were frozen in 20% sucrose with optimum cutting temperature compound (OCT) (Sakura Finetek USA Inc., Torrance, Calif.) in a 1:2 ratio respectfully using dry ice in isopentane. Cryoblocks are stored at −80° C. until sectioned. Eight um sections were cut from frozen blocks using a cryostatSections were incubated in rabbit anti-Ionised Calcium Binding Adapter 1 molecule (Iba-1) (Wako chemicals, USA), which is a microglia cell marker, and a goat anti-rabbit-Cy3 secondary antibody applied. Sections were analysed on a Zeiss 510 confocal microscope. Excitation and emission wavelengths and laser settings were identical to analyze all tissue in Intravitreal and IV injected animals. Z-stacks of sections were taken and collapsed to give an image through the depth of the whole section.

Conjugation of dendrimer conjugates. Synthesis of the dendrimer triamcinolone acetonide conjugate (D-TA) and Cy5-D-TA is shown in FIGS. 11-13 . The conjugation of dendrimers to Cy5 was done using previously reported methods (Biomaterials. 2012; 33:979-88). This is a convergent method of synthesis and a representative chromatogram is shown in FIGS. 16A-16B.

Biodistribution analysis of D-Cy5 in vital organs. Twelve BALB-C mice weighing ˜25 gr BW were used for this study. Four animals were sacrificed at each time point: 24 hours, 72 hours and 21 days. Each mouse was injected via femoral vein with 600 μg of D-Cy5 in 100 μL of sterile PBS. At respective time point, the animals were euthanized and vital organs (heart, lungs, spleen, kidney, liver and eyes) were harvested immediately and organ wet weights were noted. Organs were snap frozen on dry ice, and stored at −80° C. until analysis. Upon analysis, the tissues were thawed and approximately 100-150 mg of tissue were measured and homogenized with 1 ml of MeOH in low DNA binding tubes (Eppendorf AG, Hamburg, Germany) using stainless steel bead and tissue homogenizer (Tissuelyzer LT, QIAGEN, Hilden, Germany) resulting in a pulpy tissue suspension. The suspension was sonicated for 30 minutes and appropriate volumes containing 100 mg of tissue were placed in different low DNA binding vials and diluted with methanol to 1 ml so that the same amount of tissue and same volume was analyzed for each sample. The samples were centrifuged at 10,000 rpm for 10 minutes at 4° C. resulting in supernatants, which were subjected to fluorescence spectroscopy (FLS).

CNV rat model. Male SD rats of ˜300 grams each were chosen for this study. Lipid 3(S)-hydroperoxy-9Z,11E-octadecadienoic acid (HpODE) (Cayman Chemicals, Michigan, USA.) was dissolved in cold borate buffer at a concentration of 500 μg/33 μL. Two μL of lipid was injected sub-retinal on day 1 forming a bleb in retina. By day 3 the lipid bleb was gone and retinal degeneration began. At day 7 post-lipid injection, neovascularization from choroid (CNV) begins to form and inflammation occurs in retina and choroid as well as neovascularization in retina (RNV). This model causes damage to both choroid and retina and has characteristics of both dry and wed AMD forms (FIG. 20 ).

Statistical analysis. The data was analyzed for the reproducibility using Student's t-test to determine the significance between two groups. A p-value equal to or less than 0.05 was considered significant.

Example 1

Characterization of D-Cy5 conjugates. Ethylenediamine-core poly-(amidoamine) [PAMAM] hydroxyl-terminated generation-4 (G4-OH) were labeled with near IR fluorescent dye Cy5 as we reported previously (Molecular Pharmaceutics. 2013; 10:4560-71; Biomaterials. 2012; 33:979-88). Briefly, G4-OH was partially functionalized by 6-amino caproic acid using FMOC protection/deprotection chemistry resulting in bifunctional dendrimers with ˜5-6 NH₂ groups on their surface. The resulting bifunctional dendrimers with reactive amine groups were reacted with N-hydroxysuccinimide monoester Cy5 dye to obtain the D-Cy5 conjugate. The resulting conjugates were purified using dialysis and GPC (gel permeation chromatgraphy) and characterized using ¹H NMR (FIGS. 11-13 ).

The HPLC chromatogram of bifunctional dendrimer showed elution time of 14.84 min from the column which differed from the elution time of G4-OH dendrimer (elution time 14.42 min) (FIGS. 16A-16B). This indicates formation of a new compound and that there is only a minor shift in elution time indicating that the structural property of G4-OH dendrimer has not changed significantly. This is also congruent from the DLS results where the approximate size and Zeta potential of G4-OH dendrimer was observed (4.36±0.18 nm and +4.59±0.11 mV respectively). Also, the size and Zeta potential values of bifunctional dendrimer were 4.87±0.20 nm and 6.63±0.24 mV respectively indicating no significant change in size and surface properties of dendrimers. Appearance of a new peak simultaneously in 16.69 min at 647 nm (UV λmax for Cy5) and 645 nm (fluorescence emission of Cy5), which is different from the Cy5 peaks (20.39 min), confirms successful conjugation of dye to the dendrimers.

Example 2

Ischemia-Reperfusion: Differences in microglial/macrophage population, morphology and retinal structural changes. Iba-1⁺ resident microglia/macrophages in normal retina were less in number and had ramified morphology with distinctive dendrites. The heterogeneous populations of microglial cells were predominately found in choroid and inner nuclear layer (INL) and very few of them were observed in the outer plexiform layer (OPL) (FIGS. 2A-D; 2I-L). The retinas had a normal lamination after intravitreal injection (FIG. 2 ). I/R injury led to a structurally damaged retina and marked activation of microglia in the retina and choroid, based on a change from dendritic to round or fusiform morphology. At six days post IR, the retinal microglial/macrophages were activated and increased in number and distributed in all retinal layers: inner plexiform layer (IPL), INL, outer nuclear layer (ONL) and the subretinal space (FIGS. 3A-D). Interestingly, we found decreased numbers of choroidal microglia/macrophages. The IR injury caused collapse of inner retinal layers and retinal detachment from choroid and RPE layers, resulting in folds in retina. We also observed thinning of retinal thickness values, especially the nuclear layers in IR injured retinas when compared to normal retina suggesting neuronal and ganglion cell death (FIG. 3 ).

Example 3

Retinal biodistribution of D-Cy5 upon intravitreal & intravenous administration: Intravitreal Administration. Intravitreal administration of D-Cy5 showed differential biodistribution between normal and I/R retinas. In normal retinas at 24 hours post intravitreal injection of D-Cy5, there was very minimal fluorescence in retina and choroid (FIGS. 2A-D). There was no fluorescence signal from D-Cy5 after 24 hours suggesting that dendrimers were cleared completely from retina. On the contrary, free Cy5 remained in inner retina at 24 hours post injection (FIGS. 2D-F). This suggests that D-Cy5 is cleared rapidly from intact retina. In I/R-injured retinas, we observed significant fluorescence signal from D-Cy5 in retinal sections at 24 hours post-injection (FIGS. 3A-H). Dendrimers (D-Cy5) were observed in Iba-1+ microglia/macrophages in the subretinal space, ONL, INL and in the vicinity of internal limiting membrane (ILM) of retina. We have also observed dendrimer in vitreous and localized in other cells in inner retina and choroid. At 72 hours post intravitreal injection, D-Cy5 were cleared from other cells and vitreous in I/R eyes (FIGS. 4A-H). D-Cy5 was found within Iba-1 labeled cells and retained in microglia/macrophages near the ILM, in inner retina, and sub-retinal space (FIGS. 4A-H arrows). Interestingly, at 21 days post injection, D-Cy5 was retained specifically in microglial cells in the photoreceptor layer, IPL and near ILM (FIG. 5 ). However, in the case of free Cy5 injected animals, both I/R and normal eyes, Cy-5 can be seen in inner retina and appeared to be concentrated in blood vessels near the ILM (FIGS. 2I-L arrows) but was completely cleared by 72 hours post injection (data not shown).

Example 4

Intravenous administration. D-Cy5, free Cy5 or PBS were injected intravenously through the femoral vein six days after I/R injury in one eye. At respective time points (24 hours, 72 hours and 21 days) post injection, the eyes were enucleated for qualitative assessment of differences in retinal biodistribution of dendrimers between I/R injured and normal retina using IHC. In I/R eyes at 24 hours post intravitreal D-Cy5 administration, D-Cy5 had entered into retina from the circulation and was found within microglia/macrophages throughout retina and in the subretinal space. However, both in normal and I/R eyes 24 hours post free Cy5 dye administration, Cy-5 appeared to be present in retinal blood vessels and choriocapillaris (FIGS. 6I-L arrows). Free Cy5 was cleared at later time points. Because D-Cy5 was present in choroidal macrophages (FIG. 17 ), it appears that dendrimers can escape the normal choriocapillaris. Interestingly, we did not find any fluorescence signal from D-Cy5 in non-I/R retina indicating the intact blood retinal barrier prevented dendrimer entry. Seventy two hours post intravenous D-Cy5 injection, D-Cy5 were selectively localized and retained in microglia/macrophages in I/R retained in the subretinal space (FIGS. 7A-H arrows). Even though activated microglial cells were scattered and distributed in all retinal layers, dendrimers were found retained only in microglial cells in choroid, and in the subretinal space (FIGS. 7E-H). At 21 days post injection, D-Cy5 were retained in a few scattered in retina and choroidal microglial cells. At 21 days, there were relatively fewer Iba-1+ microglial cells with D-Cy5 compared to the 24 hour and 72 hour time point retinas. The microglial cells with D-Cy5 seemed to have reverted back to their ramified morphology but still retained D-Cy5 (FIGS. 8E-H).

Example 5

Ocular biodistribution of D-Cy5: intravitreal versus IV. The IV dose of D-Cy5 was 30-fold higher than that of the intravitreal dose. Interestingly, the qualitative uptake and retention pattern in retina was similar after both modes of administration (FIG. 10 ). This demonstrates a relatively low uptake in the healthy control eye, followed by rapid clearance, and a much higher uptake in the fellow I/R eye, and then sustained retention in the I/R eye. In fact, tyhere was no significant difference in quantitative uptake/retention pattern between the two administration modes. Even though there is some choroidal presence after IV D-Cy5 in normal eye, it appears to be mostly cleared within 72 hours (FIGS. 7I-L). In the I/R eye following IV administration, ˜40% of the D-Cy5 uptake observed after 24 hours is retained up to 21 days. For intravitreal administration, ˜16% of the D-Cy5 level from 24 hours is retained up to 21 days.

Example 6

Quantification of Iba-1+ cells and D-Cy5. Imaris software was used to count the number of Iba-1+ cells in 8 mm cryosections from ora serrata to ora serrata. Four sections from each group were counted. There were significantly more Iba-1+ cells in I/R eyes than non-I/R eyes (FIG. 9A). The software counts not just a single label but cells with two labels colocalizing. FIG. 9B demonstrates the cells selected by the software that have both labels (arrowheads) after setting parameters that only cell somas would be counted and not delicate processes. We determined that a significant number of Iba-1+ cells had D-Cy5 at all time points with both modes of D-Cy5 delivery (FIGS. 9C-D) because no cells were double labeled in non-I/R retinas.

Example 7

Quantitative biodistribution of D-Cy5 in vital organs. Quantitative biodistribution in vital organs (liver, kidney, spleen, heart, lungs and serum) and kinetics of D-Cy5 injected intravenously into animals with I/R injury was assessed using FLS (fluorescence spectroscopy) method. For analysis, weight of tissues was measured before being homogenized and D-Cy5 was extracted using methanol as described previously by Lesniak et al. (Molecular pharmaceutics 10 (12), 4560-4571). The D-Cy conjugates were intact stable in human plasma at 37° C. and in vivo, and also the applied methanol extraction protocol yielded best recovery of 96%. The methanol extracts were subjected to fluorescence measurements for emission values using fluorescence spectrophotometer. The amount of D-Cy5 accumulated in each organ was calculated by incorporating the emission values (subtracted background from emission values of respective organs injected with PBS) into the calibration graphs and the values were then back calculated to % of injected dose (ID)/organ using whole organ wet weights.

Upon intravenous injection, a percentage of D-Cy5 was immediately cleared out from circulation via urine. We observed that the animals injected with D-Cy5 or free Cy5 urinated deep blue urine within ˜5-7 minutes. Twenty four hours post injection, the majority of D-Cy5 was cleared from blood plasma but retained in differential amounts in vital organs (FIG. 15 ). At 24 hours according to FLS analysis ˜0.18% of the injected dose was still in blood. The total blood volume for BALB/C mice is 10.35±0.16 ml/g of tissue.

Confocal microscopy analysis of the kidney sections (FIG. 18 ) revealed high D-Cy5 signal in the proximal tubules of the kidney cortex at 24 hrs (FIG. 18A), with this signal decreasing by 72 hrs (FIG. 18B), which is in good agreement with the biodistribution data. The HPLC of the kidney extracts at 24 hrs showed a small peak from free Cy5 but the major fraction of the peak was D-Cy5 (FIG. 18D). Based on HPLC calibration, we estimate that 12% of the conjugated Cy5 was released by this time, suggesting that the conjugates are mostly intact in-vivo. Hematoxylin and eosin staining of kidney sections from animals injected with D-Cy5 showed no neutrophil or monocyte infiltration, no structural damage, or any signs of toxicity (FIGS. 18G-I).

The injected D-Cy5 conjugates were cleared but some accumulated in the kidneys (FIG. 18 ). This is in good agreement with the previous results based on fluorescence measurements as described above, and radiolabelling (Drug Deliv Transl Res. 2013 Jun. 1; 3(3):260-271). The D-Cy5 biodistribution and accumulation is as follows: kidney (29.98±2.5%), liver (11.19±2.2), and spleen (3.33±1.26) (FIG. 15 ). Heart and lungs had minimal accumulation of D-Cy5 (0.0049% and 0.01% respectively). Free Cy5 on other hand was found to be rapidly cleared from blood and had significantly lower accumulation of 0.82±2.93% of the injected dose in kidneys in 24 hours. Moreover, we could not detect any fluorescent signals in other organs indicating the free Cy5 has rapid clearance. At 72 hours post injection, D-Cy5 was cleared from heart, lungs, and spleen but found predominately and persistently retained in kidneys (5.53±1.5%) and to very little extent in liver (0.73±0.026%). Free Cy5 was not detectable in any of the organs indicating that they were either cleared from the body or the amount was below limits of detection (LOD). Twenty one days post injection, dendrimers were completely cleared from all organs examined.

Because there was predominant accumulation of D-Cy5 in kidneys, a qualitative microscopic analysis was done using confocal microscopy. At 24 hours the signal intensity of D-Cy5 channel was high in proximal tubules (FIG. 17 ) of the kidney cortex but the signal intensity was decreased in 72 hours kidneys, which is in good agreement with the biodistribution data. The kidney extracts were also analyzed using HPLC to confirm that the fluorescence emission is from D-Cy5 or free Cy5 species. The HPLC chromatograms of the kidney extracts at 24 hours showed a small peak from free Cy5 but the major fraction of the peak was D-Cy5. Twelve % of the conjugated Cy5 was released, based on the calibration graphs of free Cy5, suggesting that the conjugates are somewhat intact in-vivo up to 72 hours. The H and E analysis on these kidney sections (data not shown) show no neutrophil or monocyte infiltration, no structural damage or any signs of toxicity suggesting that the injected D-Cy5 dose did not inflict any toxic effects to organs.

Example 8

Dendrimer-uptake in the posterior eye-cup. The dendrimer uptake was assessed in the injured and non-injured eyes upon systemic (FIG. 19 , Panel A) and intravitreal (FIG. 19 , Panel B, at 30-fold lower doses), using tissue isolation of D-Cy5 and fluorescence quantification. Interestingly, our studies show a significantly higher uptake and retention of the dendrimer in the injured I/R eye, even up to 21 days, post systemic administration. Surprisingly, between 24 hours and 21 days, there appears to be only a 50% drop in the dendrimer level in the injured eye. In contrast, the dendrimer appears to be largely cleared from the healthy eye within 72 hours. The fact that the dendrimers are selectively present in the inflammatory cells, suggests that systemic therapies with dendrimers are viable and sustainable over many weeks. In contrast, small drugs, administered either intravenously and intravitreally are readily cleared from the eye over a short period of time.

Example 9

Effect of N-acetal-Cysteine (NAC) on CNV model. A combination of D-NAC (dendrimer-NAC; 10 mg/kg on a NAC basis) and 6 mg of D-Cy5 were injected intravenously via penile vein on day 3 post lipid injection and animals were sacrificed on day 7 post injection. The animals injected with D-Cy5 and PBS served as controls. The eyes were enucleated immediately after sacrifice and fixed, and retinas and choroids stained with Microglia/Macrophage specific antibody Iba-1, blood vessels stained with GSA lectin and the nuclei were stained with DAPI then viewed as separate flat mounts initially with a Zeiss Meta710 confocal microscope. After flatmount analysis, the tissues were cryopreserved separately and frozen in OCT/20% sucrose. The confocal images choroids of D-NAC treated and control groups were analyzed for CNV area measurements using Image-J software.

The image analysis confirmed that lipid injection caused a strong inflammatory response in choroids resulting in the micro glial/macrophage (Iba-1 Green) activation, migration and accumulation in CNV area (Iso-lectin blood vessel labeling, Blue) (FIG. 21 ). The results suggest that systemically administered dendrimers localized specifically in Iba-1 positive cells in the CNV area (Cy5-Red). The D-NAC+D-Cy5 groups showed therapeutic efficacy in reducing the CNV area when compared to D-Cy5 injected groups. D-NAC (20 mg/kg) was administered systemically, 3 days after lipid-administration, on Day 3, and Day 6, and animals were sacrificed on Day 10. The D-NAC treated animals showed a significant, unexpected reduction in CNV (˜80%) (FIG. 22 ).

Dendrimers can deliver NAC specifically to inflammation causing cells, thereby attenuating them, and which in turn, decreases the VEGF production thus controlling the neovascularization. Retina flat mount images show that D-Cy5 is up taken by retinal microglia in the inflammation area (FIG. 23 ). It is also evident that the microglial cells are activated due to inflammation caused by the lipid (similar to dry AMD) and the lipid and microglia inducing growth of new blood vessels (similar to wet AMD). We have also observed the migration of microglial cells towards the inflammation area in retina (FIG. 24 ).

Example 10

Systemically administered D-NAC conjugate suppresses CNV, when administered early. D-NAC was administered on Day 3 (two days after lipid administration), and on day 5 and day 7 at 20 mg/kg on a NAC basis. D-NAC caused significant suppression of CNV when assessed on Day 10 compared to free NAC at equivalent doses, and untreated controls (˜78% suppression compared to PBS, n=12 eyes, p<0.001). As shown in FIG. 25 , the effect of systemic free NAC, D-NAC (20 mg/kg on NAC basis), or PBS, on CNV, was assessed in a blinded manner, using established choroidal flat mount protocols. D-NAC treated animals showed significant decrease in CNV areas when compared to PBS. Free NAC showed some decrease that was not significant. CNV areas were assessed using morphometric analysis (yellow delineation) in Image-J software. FIG. 25 , Panel A shows the PBS choroid with larger CNV and increased population of macrophages (green) in the bleb area, whereas FIG. 25 , Panel B shows the efficacy of D-NAC with reduced CNV and macrophage accumulation. The vasculature was stained with GSA lectin (blue), and macrophages are stained with IBA-1 (Green). Values were analyzed using Mann-Whitney t-test with n=12 and P<0.001

Example 11

Systemic D-NAC reduces macrophage migration to the CNV area, and attenuates choroidal inflammation. The extent of macrophage depletion in the CNV region, upon systemic D-NAC therapy at 20 mg/kg NAC was assessed on Day 10, using IBA-1 staining. A significant reduction in total macrophages accumulation (˜63%) was seen upon D-NAC therapy. Previous studies by Ambati and coworkers showed that macrophage depletion correlated with CNV reduction. Interestingly, morphological analysis using Imaris71 suggested that there was an 80% reduction in activated macrophages, and ˜90% of these activated macrophages contained D-Cy5 (in both PBS and D-NAC treated animals), indicating selectivity (FIG. 26 ).

Example 12

The effect of D-NAC choroidal inflammation was assessed in a blinded manner, by measuring proinflammatory (IL-1β, IL-6, MCP-1-monocyte chemoattractant, and TNFα) and anti-inflammatory cytokine levels (IL-10). 10,23,72 There was a significant reduction in all the proinflammatory cytokines, which returned to levels seen in healthy controls, whereas free NAC was not effective (FIGS. 27A & B). Interestingly, D-NAC appeared to enhance the anti-inflammatory cytokine IL-10 (FIG. 27C). This suggests that selective attenuation of proinflammatory response can be achieved with D-NAC.

Example 13

Systemic dendrimer targets retinal mi/ma, and D-NAC attenuates retinal inflammation. Similar to the biodistribution pattern seen in the CNV area, the D-Cy5 localized selectively in the activated mi/ma in the bleb area (FIG. 28B), but did not localize in the unaffected areas of the same retina (FIG. 28A). In D-NAC treated retina, there was a reduction in the number of mi/ma in the bleb area, and which were more ramified with less D-Cy5 uptake.

The effect of D-NAC on retinal inflammation was assessed in a blinded manner, by measuring proinflammatory (IL-1β, IL-6, MCP-1, and TNFα) and anti-inflammatory (IL-10) cytokine levels. There was a significant reduction in all the proinflammatory cytokines, which returned to levels seen in healthy controls, whereas free NAC was not effective (FIGS. 30A & B). Interestingly, D-NAC appeared to enhance the anti-inflammatory cytokine IL-10 (FIG. 30C). This suggests that selective attenuation of proinflammatory response can be achieved with D-NAC.

Example 14

Systemic combination therapy with D-NAC and D-TA, results in CNV regression. A combination of D-NAC (20 mg/kg on NAC basis) and D-TA (10 mg/kg on TA basis) was administered systemically at a later stage (on Day 11, Day 13 and Day 15) to assess the efficacy when significant CNV has already occurred: (1) On Day 21, there was a 72% reduction in CNV in dendrimer-treated animals, compared to PBS controls, suggesting that late treatment is effective; (2) Compared to the extent of CNV area on Day 10, there was a ˜45% reduction in dendrimer-treated animals on Day 21, showing strong suggestions of CNV regression (FIGS. 31-33 ). These pilot results (n=3) suggest that significant CNV suppression may be possible with systemic therapies delivered with dendrimers. The systemic combination therapy did not lead to any increase in IOP, or any systemic toxicity assessed from histology. Moreover, as shown in FIG. 34 , both intravitreal and systemic administration of the inventive compositions had similar retinal biodistribution and effect in injured retinas, meaning the systemic administration is a viable alternative to intravitreal injection.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

1-13. (canceled)
 14. A method for treating an inflammatory disease of the eye in a subject in need thereof, the method comprising: systemically administering to the subject a dendrimer composition in an amount effective to treat the inflammatory disease in the eye of the subject, wherein the dendrimer composition comprises a hydroxyl-terminated dendrimer conjugated to one or more therapeutic agents.
 15. The method of claim 14, wherein the inflammatory disease of the eye is macular degeneration, macular edema, retinal vein occlusion, or geographic atrophy.
 16. The method of claim 15, wherein the macular degeneration is wet age-related macular degeneration.
 17. The method of claim 15, wherein the macular edema is diabetic macular edema.
 18. The method of claim 15, wherein the retinal vein occlusion is branch retinal vein occlusion.
 19. The method of claim 14, wherein the administering comprises intravenous or subcutaneous administration.
 20. The method of claim 14, wherein the one or more therapeutic agents are selected from proteins, oligonucleotides, and small molecules.
 21. The method of claim 20, wherein the one or more therapeutic agents are selected from enzymes, hormones, growth factors, antibodies, receptor antagonists or agonists, siRNA, and microRNA.
 22. The method of claim 21, wherein the one or more therapeutic agents are selected from anti-VEGF agents, COX-2 inhibitors, and antagonists of NF-κβ.
 23. The method of claim 20, wherein the one or more therapeutic agents are selected from N-acetyl-cysteine (NAC), triamcinolone acetonide, methyl prednisone, dexamethasone, minocycline, SN50, aflibercept, rapamycin, vitamin A, vitamin C, vitamin E, and beta-carotene.
 24. The method of claim 14, wherein the dendrimer composition is formulated in a liposome, a microcapsule, or a nanocapsule.
 25. The method of claim 14, wherein the hydroxyl-terminated dendrimer is a poly(amidoamine) (PAMAM) dendrimer.
 26. The method of claim 14, wherein the hydroxyl-terminated dendrimer is a generation 3, generation 4, generation 5, generation 6, generation 7, generation 8, generation 9, or generation 10 dendrimer.
 27. The method of claim 14, wherein the dendrimer composition is administered to the subject daily, weekly, monthly, or bimonthly.
 28. A method for detecting an inflammatory disease of the eye in a subject in need thereof, the method comprising: systemically administering to the subject a dendrimer composition in an amount effective to detect the inflammatory disease in the eye of the subject, wherein the dendrimer composition comprises a hydroxyl-terminated dendrimer conjugated to one or more imaging agents.
 29. The method of claim 28, wherein the inflammatory disease of the eye is macular degeneration, macular edema, retinal vein occlusion, or geographic atrophy.
 30. The method of claim 29, wherein the inflammatory disease of the eye is wet age-related macular degeneration, diabetic macular edema, or branch retinal vein occlusion.
 31. The method of claim 28, wherein the administering comprises intravenous or subcutaneous administration.
 32. The method of claim 28, wherein the imaging agent is a fluorescent dye.
 33. The method of claim 28, wherein the hydroxyl-terminated dendrimer is a generation 3, generation 4, generation 5, generation 6, generation 7, generation 8, generation 9, or generation 10 PAMAM dendrimer. 